Electric switch



E. LANGE ELECTRIC SWITCH Filed Feb.' 10, 1932 @MJA-law C0, REsfRra/z Patented Oct. 22, 1935 PATENT OFFICE misuse ELECTRIC SWITCH Emil Lange, Berlin, Germany Application February 10, 1932, Serial No. 592,093

In Germany January 12, 1930 6 Claims.

This invention relates to improvements in electric switches, more particularly to switches the contact members of which'are arranged within a pressure chamber or pressure retaining vessel.

In switches of this type, when the arc is formed between the separating contact members, an increase in pressure occurs within said vessel. This increase in pressure causes a stream of liquid or gases to ilow between the separating contact 10 members extinguishing the arc and preventing the contact members to be damaged.

One object of the invention is to extinguish the arc without any quenching liquid. 'Ihe use of oil isl open to the objection that vapors are produced which, when ignited, cause the' explosion of the switch. On the other hand, switches provided with an electrolyte e. g. water as a quenching liquid are open to the disadvantage of the formation of oxyhydrogen which on being ignitedl causes alsov an explosion of the switch.

Another object of the invention is to provide means for strongly cooling the separating contact members.

Another object of the invention is to provide means for preventing a blast of gases to be directed into the path of the arc before a predetermined increase in pressure occurs within the pressure retaining vessel.

Other objects of the invention will appear from the following description in connection with the accompanying drawing in which several embodiments of the invention are illustrated diagram matically by way of example.

Fig. 1 shows a switch with a pressure chamber or pressure retaining vessel surrounding the cooled point of break.

Fig. 2 is a switch similar to that shown in Fig. 1, but with two points of break.

Fig. 3 shows a switch with a pressure chamber surrounding the break point and connected to a pressure gas bottle through a valve.

Fig. 4 shows a switch similar to that illustrated in Fig. 3. In a compartment 85 (Fig. 1), which may be of rectangular or circular shape, and which constitutes the pressure or arc chamber, contacts 2| and 22 are arranged. 'I'he contact bolt 2| is movable and actuated from outside by anordinary i driving mechanism (not shown) for making and breaking the contact with the contact member 22. The wall 23 of the pressure chamber 85 is made of an electric and heat insulating material, such as porcelain. The stationary contact 22 is hollow and the hole of this contact forms the sole gas outlet of the pressure chamber 8l, thus compelling the compressed gas to blow out through the arcing spot. The gas outlet proper of the switch lies'immediately behind the perforated or hollow contact 22. This outlet is closed by a weighted or spring-controlled closing element or 5 valve 24, which opens towards the outer room under the effect of an inner over pressure of a predetermined value and closes`when the pressure in the compartment drops. For increasing the heat insulation of the compartment 85, a 1 casing 25 is provided, and the space 26 between the walls of said casing and the walls 23 of the chamber 85 is lled with lcork or similar heatl insulating material. In the compartment 85, cooling means' for the contact members 2| and u 22 are further provided for example, a container- 29, filled with carbon dioxide, which gives off cold vwhile evaporating to the gas contained in chamber 85. Closing means 38 are disposed in an opening 3| in the walls A23 and 25 to enable the zo reiilling of the container 29. This opening 3| also ensures an easy control oi' the switch contacts.

The switch operates in the following manner:

An a'rc forms in the compartment 85 when thc 25A contacts 2| and 22 are separated. This arc has a high temperature. There is a considerable rise in pressure in the air or gas in the chamber produced by the heat of the arc. The temperature of the gaseous medium filling the compartment 85 30 is at the same time strongly diminished by the carbon dioxide evaporating in the container 29. The relatively great temperature difference lbetween the arc and the surrounding atmosphere thus obtained and the relatively'great pressure u rise thereby created cause a strong outflow of carbon dioxide through the tubular contact 22 and through the outlet of the valve 24, which is the more increased, theimore the gas included in o chamber 85 is cooled due to the evaporation of carbon dioxide. Owing to the sudden increase of pressure in the compartment 85, the valve 24 becomes opened so that the gas, under high pressure, quickly escapes. Thus, the arc between the contact members 2| and 22 is quickly extinguished. The compartment 85' remains, after the switching-oil operation, i. e., after the extinguishing of the'arc, filled with carbon-dioxide gas at a certain pressure determined by the spring of the valve 2l. This pressure is preferably considerably above atmospheric, as itis then necessary to impart to the gaseous medium in the chamber a relatively small quantity of heat by the arc' in order to get the rise in pressure wanted for expelling the gases and extinguishing the arc rapidly. This is particularly true for small arcs, i. e.. when the power to be switched off is small. Apparently, the extinguishing of an arc by evaporating carbon dioxide is much more effective than by air, but the invention is applicable to use with strongly cooled air` also.

A switch with two make-and break contacts, main and auxiliary, is illustrated in Fig. 2.

A movable traverse 34. actuated by a driving rod 35, is situated in the compartment 32 and provided with two contact members 33 and 33' adapted to co-operate with contact members 35 and l1. 'I'he contact member l1 is hollow, permitting the outflow of compressed gas and the contact member 36 is solid. The main contact members 33, I1 are connected to the auxiliary contact members Il' and 35. 'Ihe contact members 34 and 31 are fixed in the inner wall 38 of a casing surrounding the pressure chamber 32, the hollow walls of which casing are preferably illled with heat and electric insulating material. Cooling means 39, similar to the cooling means 29 oi Fig. 1, are located in the compartment, accessible through an aperture 4| that may be closed by a closing means 4Il. These cooling means may consist, for instance, of carbon dioxide snow, thus developing at the same, time gas and cold. Ihe

-ho1low formed in the contact member 31 is closed by a valve 42 (that may 4be held closed in the same manner as the valve 24), as long as there takes place no interruption of the contact members being under voltage. 'I'he pressure compartment 82 is on its outside provided with a wall 43, that forms a pressure-proof casing for the hollow rooms filled with thermo-insulating material.

The valve 42 of Fig. 2, like the valve 24 of Fig. 1, is adjusted toallow the gases produced in the compartments Il and 32, respectively, to ilow out therefrom only after a certain pressure is reached. Thearcisextinguishedinthesamemanneras before described. the auxiliary contact members Il and 88 connected in series to and co-operating with the main contact members ll and" as is customary in devices of this-nature. The are produced by the auxiliary contact members Il' and 38 will produce a considerable increase in pressure in the chamber 32. This gas pressure will naturally become increased upon the opening of the main contact members Il and Il, with the result that the gases will be forced out of the chamber 32. through the valve42, with a corresponding high speed and despatch.

Instead of maintainingr a reserve of carbon dioxide snow in the pressure chamber Il.' which must be replenished from time to'time, liquid carbon dioxide may be supplied in such a manner to the pressure chamber, that it is converted into carbon dioxide snow on entering the Lpressure Fig. 3 illustrates a switch of this kind with a pressure chamber surrounding the point of break 45, 46 and connected by a valve to a container containing liquid carbon dioxide.

In the pressure chamber 44, the stationary oontact'member 45forming a hollow contactandl the movable contact 45 forming a pin, are arranged. An admission nozzle 41 is provided, in the -lower portion of the pressure chamber 44, -for introducing the compressed gas necessary for continuously maintaining the gas pressure in the chamber. v'The pressure chamber is kept closed above the stationary hollow contact member 45 by a spring-closing valve 4I or the 1ike.\ The pressure chamber communicates with a gas cylinder 50 filled with liquid gas, for'instance, carbon dioxide, through a pipe conduit 4l. -A reducing valve 5I serves for regulating the pressure to be maintained continuously, when the contact members are closed, and the force of the permanent gas iiow dependent on said pressure.

T'he switch shown in Fig. 'operates in the ioll lowing manner: v

Pressure is produced and maintained in the pressure chamber 44 by the gas entering from the gas cylinder 55. 'I'he 4i'orce of this pressure in the pressure chamber 44 is maintained suitably reduced at a substantially constant or uniform value by means of the reducing valve 5i to prevent opening of the valve l4l.

The arc produces an increase of pressure in the pressure chamber 44 during the separation of l5 the contact members 45 and 4B. Owing to this increase in pressure, the valve 48 becomes opened to permit the gas produced to flow intensely through the hollow contact member 45, thus to extinguish the arc.

The special advantage of this arrangement lies in the continuously existing uniform pressure in the pressure chamber, as long as no switching-olf takes place, making it unnecessary to adjust the Ivalve through which the gases are forced to extinguish the arc.

As shown in Fig. 4, a reserve of carbon dioxide or other cold-producer |05 ls always present in the pressure chamber 44.

For this purpose, the pressure vessel 55 filled 80 with liquid carbon dioxide is so arranged, as by turning it upside down, as compared with Fig. 3, that liquid carbon dioxide fills the connecting conduit 49, and, on leaving a nozzle 41 projecting into the pressure chamber, can evaporate and solidify to form carbon dioxide snow I ll. The nozzle 41 is preferably made adjustable in order that the quantity of carbon dioxide snow to be formed may be regulated. A reducing valve inserted in the conduit `is permanently open. ^0

The above described invention has important advantages over the high-eillciency switches of the prior art. Owing to the strong pre-cooling vetl'ect of the carbon-dioxide gas surrounding the switch contact members, a considerably greats' 4l increase of pressure will be produced by the arc in the pressure chamber, and consequently a more rapid extinction of the arc will take place occurs in other switches.

What is claimed is:

1. An electric switch of the type in which the contact is made within a gaseous medium having. inV combination, a pressure chamber provided with an outlet, a stationary contact member disposed 1n the path or the gas sowing into me outlet, s W movable contact member within said pressure chamber for co-operating with the stationary contact member, a valve in the pressure chamber for normally closing the' outlet, and means operable independently of the movement of the movo able contact member for automatically opening the valve when the pressure in the pressure chamber rises to a predetermined value.

y 2. An electric switch o'i' the type in which the contact is made'wlthm sgaseous medium having, in combination, a pressure chamber provided with an outlet, a hollow stationary contact member disposed near the outlet, a movable contact member within said pressure chamber for co-operating 7 with the stationary contact member, a valve in the pressure chamber for normally closing the outlet, and means operable independently of the movement of the movable contact member for automatically opening the valve when the presn :,oiaiss, l 3

Vsurelnthepressure chamberrisestoaprede- 4termined value.

s. An electric switch or the type in which the contact is made within azgaseous medium having.

in combination, a pressure chamber provided with an outlet, a stationary contact member disposed near the outlet, a movable'contaet member within said pressure chamber for co-operatingwith the stationary contact member, a valve in the pressure chamber for normally closing the outlet, means operable independently of the movement oi the movable contact, member for automatically opening the valve when the pressure in the pressure chamber rises to a predetermined value, and a volatile. coldfgenerating medium in the pressure chamber for cooling the gaseous medium therein.

4. An electric switch of the type in which the contact is made within a gaseous medium having. in combination, a pressure chamber provided with an outlet, a hollow stationary contactv member disposed near the. outlet, a movable contact member within said pressure chamber for co-operating with the stationary contact member, a valve in the pressure chamber for normally closing the an outlet, a stationary contact member disposed near thevoutlet, a movable contact ,member with- C in said pressure chamber for co-operating with the stationary contact member, a valve in the pressure chamber for normally closing the outlet, means operable-independently of the movement oi' the movable contact member for automatically 5 opening the valve'when the pressure in the pres--v sure chamber rises to a predetermined value,l a vessel for containing gas under pressure, a conduit connecting the vessel with the pressure chamber, and a reducing valve in the conduit, the 10 reducing valve being adjustable to maintain the gas pressure permanently present in the pressure chamber below the said predetermined value.

6. An electric switch of the type in which the contact is made .within a gaseous medium having, l5 in combination, a pressure chamber provided with an outlet, a stationary contact member disposed near the outlet, a movable contact member within said pressure chamber for co-operating with the stationary contact member, a vvalve. in the 20` pressure chamber for normallyvclosing the outlet, means operable independently of the movement of the movable contact member for automatically opening the valve when the pressure in the pressurechamber rises to a predetermined value,

'Y a vessel'for containing gas under pressure, a'

conduit connecting the vessel with the pressure chamber, a reducing valve in the conduit, the reducing valve being adjustable to maintain the gas pressure permanently present in-the pressure chamber below the said predetermined value, the

vessel being disposed top-side down above the conduit, whereby liquid carbon dioxide contained therein ilows into the conduit, anda nozzle in ghe pressure chamber connected with the con-* uit.

EMIL LANGE. 

